#include<stdio.h>

int Sum(int s, int e)
{
    int sum = 0;
    int i = s;
    for(; i <= e; i++)
    {
        sum += i;
    }
    return sum;
}

int Add(int x, int y)
{
    return x + y;
}

int div(int x, int y)
{
    if( y == 0) return -1;
    int z = x / y;
    return z;
}

int main()
{
    printf("process is running\n");
    
    int start = 1;
    int end = 100;
    int result = Sum(start, end);
    printf("process is done, result: %d\n", result);
    
    int a = div(10, 0);
    printf("process is done, div result: %d\n", a);
    
    int b = Add(10, 20);
    printf("process is done, Add result: %d\n", b);

    return 0;
}
